Fine-scale Weather Patterns Drive Reproductive Success in the Brown Pelican

Waterbirds ◽  
2021 ◽  
Vol 44 (2) ◽  
Author(s):  
Rochelle A. Streker ◽  
Juliet S. Lamb ◽  
John Dindo ◽  
Patrick G. R. Jodice
2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
Stephen L. Webb ◽  
Kenneth L. Gee ◽  
Bronson K. Strickland ◽  
Stephen Demarais ◽  
Randy W. DeYoung

Few studies have documented fine-scale movements of ungulate species, including white-tailed deer(Odocoileus virginianus), despite the advent of global positioning system (GPS) technology incorporated into tracking devices. We collected fine-scale temporal location estimates (i.e., 15 min/relocation attempt) from 17 female and 15 male white-tailed deer over 7 years and 3 seasons in Oklahoma, USA. Our objectives were to document fine-scale movements of females and males and determine effects of reproductive phase, moon phase, and short-term weather patterns on movements. Female and male movements were primarily crepuscular. Male total daily movements were 20% greater during rut () than postrut (). Female daily movements were greatest during postparturition (), followed by parturition (), and preparturition (). We found moon phase had no effect on daily, nocturnal, and diurnal deer movements and fine-scale temporal weather conditions had an inconsistent influence on deer movement patterns within season. Our data suggest that hourly and daily variation in weather events have minimal impact on movements of white-tailed deer in southern latitudes. Instead, routine crepuscular movements, presumed to maximize thermoregulation and minimize predation risk, appear to be the most important factors influencing movements.


2018 ◽  
Vol 8 (23) ◽  
pp. 11634-11644 ◽  
Author(s):  
Nancy E. Roney ◽  
Rebekah A. Oomen ◽  
Halvor Knutsen ◽  
Esben M. Olsen ◽  
Jeffrey A. Hutchings

2021 ◽  
Vol 17 (6) ◽  
pp. 20210097
Author(s):  
Sara Labrousse ◽  
Alexander D. Fraser ◽  
Michael Sumner ◽  
Frédéric Le Manach ◽  
Christophe Sauser ◽  
...  

In a fast-changing world, polar ecosystems are threatened by climate variability. Understanding the roles of fine-scale processes, and linear and nonlinear effects of climate factors on the demography of polar species is crucial for anticipating the future state of these fragile ecosystems. While the effects of sea ice on polar marine top predators are increasingly being studied, little is known about the impacts of landfast ice (LFI) on this species community. Based on a unique 39-year time series of satellite imagery and in situ meteorological conditions and on the world's longest dataset of emperor penguin ( Aptenodytes forsteri ) breeding parameters, we studied the effects of fine-scale variability of LFI and weather conditions on this species' reproductive success. We found that longer distances to the LFI edge (i.e. foraging areas) negatively affected the overall breeding success but also the fledging success. Climate window analyses suggested that chick mortality was particularly sensitive to LFI variability between August and November. Snowfall in May also affected hatching success. Given the sensitivity of LFI to storms and changes in wind direction, important future repercussions on the breeding habitat of emperor penguins are to be expected in the context of climate change.


Author(s):  
Russell L. Steere

Complementary replicas have revealed the fact that the two common faces observed in electron micrographs of freeze-fracture and freeze-etch specimens are complementary to each other and are thus the new faces of a split membrane rather than the original inner and outer surfaces (1, 2 and personal observations). The big question raised by published electron micrographs is why do we not see depressions in the complementary face opposite membrane-associated particles? Reports have appeared indicating that some depressions do appear but complementarity on such a fine scale has yet to be shown.Dog cardiac muscle was perfused with glutaraldehyde, washed in distilled water, then transferred to 30% glycerol (material furnished by Dr. Joaquim Sommer, Duke Univ., and VA Hospital, Durham, N.C.). Small strips were freeze-fractured in a Denton Vacuum DFE-2 Freeze-Etch Unit with complementary replica tooling. Replicas were cleaned in chromic acid cleaning solution, then washed in 4 changes of distilled water and mounted on opposite sides of the center wire of a Formvar-coated grid.


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